1. Field of the Invention
The present invention is directed to a simulator and, more particularly, to a metabolic simulator (MS) or a respiratory metabolic simulator (RMS), wherein carbon dioxide (CO2) is supplied and/or oxygen (O2) is removed using a cell that produces CO2 and depletes O2, e.g., a direct methanol fuel cell (DMFC).
2. Description of Related Art
For the purpose of providing a realistic “load” for life-supporting devices and environments it is sometimes necessary to simulate a human's impact as far as exhaled breathing gases and caloric output are concerned. Simulators to that effect are called metabolic simulators (MS) or respiratory metabolic simulators (RMS). It is not always necessary to mimic all output gas concentrations with high fidelity or the dissipation of heat caused by the presence of a person, so that for some purposes the addition of CO2 to the gas exhaled by a breathing simulator is sufficient.
The prior art relating to the addition of CO2 and/or removal of O2 in a full RMS discloses a means for controlled combustion of organic fuels (U.S. Pat. No. 3,049,812 to Bovard) and a system for full or partial gas substitution (U.S. Pat. No. 5,584,701 to Lampotang et al.; and Duffield et al., “Redesign of the Human Metabolic Simulator, SAE Publication No. 2004-01-2497, 34th International Conference on Environmental Systems (ICES), Jul. 19-24, 2004). In addition, using a hydrogen-fueled catalytic process as a means of O2 reduction and CO2 production has been disclosed (U.S. Pat. No. 6,957,651 to Nuckols et al.) but has not been implemented in the NASA Human Metabolic Simulator due to safety concerns and other technical considerations.
As can be appreciated by those skilled in the art, it would be advantageous to provide an MS and/or an RMS that has a process to reduce O2 and to produce CO2 that does not have the limitations of the hydrogen-fueled catalytic process of the prior art.